Heterostructure design to achieve high quality, high density GaAs 2D electron system with $g$-factor tending to zero

TL;DR

This paper presents a heterostructure design that maintains high density in GaAs 2D electron systems under hydrostatic pressure, enabling exploration of electron interactions at near-zero g-factor.

Contribution

The study introduces a heterostructure approach that suppresses density decrease under pressure, allowing high-quality, high-density GaAs 2DES with tunable g-factor.

Findings

Pressure-dependent conduction band alignment explains g-factor changes.

Heterostructure design reduces density loss by over threefold.

Enables investigation of electron interactions at g≈0.

Abstract

Hydrostatic pressure is a useful tool that can tune several key parameters in solid state materials. For example, the Land\'e $g$-factor in GaAs two-dimensional electron systems (2DESs) is expected to change from its bulk value $g\simeq-0.44$ to zero and even to positive values under a sufficiently large hydrostatic pressure. Although this presents an intriguing platform to investigate electron-electron interaction in a system with $g=0$, studies are quite limited because the GaAs 2DES density decreases significantly with increasing hydrostatic pressure. Here we show that a simple model, based on pressure-dependent changes in the conduction band alignment, quantitatively explains this commonly observed trend. Furthermore, we demonstrate that the decrease in the 2DES density can be suppressed by more than a factor of 3 through an innovative heterostructure design.